Improving health related quality of life (HRQOL) is a major goal in the treatment of all chronic illnesses. In addition, there is growing consensus that assessment of quality of life is crucial to provide a complete picture of children's physical and mental health status. To our knowledge there are no HRQOL instruments specifically developed for adolescents with mental health problems. Therefore, the central goal of the proposed application is to develop, test, and validate an adolescent HRQOL instrument for mental health [AQOL-MH) in Spanish and English. This will provide a culturally valid outcome measure that will contribute to reduce mental health care disparities. This instrument will help mental health professionals focus on particular HRQOL domains during the diagnostic process; thereby assisting both patients and providers set, define and evaluate adequate treatment goals. This proposal presents a unique opportunity for a young faculty with extensive experience in behavioral sciences research, to advance her career and obtain independent funding. The ultimate objective of this proposal is to develop ah RO1 application to administer the AQOL-MH to representative clinical samples in order to target its usefulness in evaluating clinical effectiveness in treatment programs and interventions. The specific aims of this proposal are the following: Aim 1: To develop themes that respond to the construct of quality of life as perceived by adolescents who are receiving services for mental health problems in Puerto Rican and Mexican American, as well as Anglo populations. The development will be achieved using a grounded theory approach with the use of focus groups and in-depth interviews of clinical samples of Latino and US non-Latino youth who are recruited to have one of four prevalent mental disorders; ADHD, Conduct Disorder, Generalized Anxiety, and Depression. Aim 2: To test the psychometric properties of the measure developed in Aim 1 using clinical and nonclinical samples of youth from Puerto Rico and the US. Psychometric analyses will include assessments of internal structure, tests for differential item functioning across Latino and non-Latino as well as gender groups, and preliminary tests of construct validity. Aim 3: Test the usefulness of the short-form AQOL-MH for tracking change during the course of service use in evidence based practice among youth with ADHD and Depression disorders in Puerto Rico. To achieve this aim we will recruit 60 youth who begin to receive treatment and we will obtain a baseline and two repeated assessments of HRQOL at six month intervals.